The aircraft collided with a tree during a go-around at night following a downwind precautionary landing. During the flight, the pilot had noted the fuel gauges at low readings and said he suspected a 'fuel leak'. He made radio calls to try to go to an airport before fuel exhaustion. Shortly after radio contact was made, communications were lost and an electrical failure was experienced. The pilot descended below the clouds. He abandoned one approach because the field looked 'short and soggy.' The next approach to another field was missed, he said, because of a tailwind. During the go-around, the engine quit and the aircraft collided with a tree. Examination of the aircraft after the accident showed the alternator circuit breaker popped. The alternator was removed and tested. It produced a voltage indication at 700 RPMs to 4500 RPMs. Maximum voltage was 30 volts. The low voltage light bulb was incorrect and the wiring was disconnected. The weather at accident time was conducive to carburetor icing.